"We cannot make claims as to the 1990s being the warmest decade."

Take the grand claim made by some climate researchers that the 1990s were the warmest decade in the warmest century of the past millennium. This claim is embodied in the famous "hockey stick" curve, produced by Michael Mann of the University of Virginia in 1998, based on "proxy" records of past temperature, such as air bubbles in ice cores and growth rings in tree and coral. (see "Hotly contested") Sceptics have attacked the findings over poor methodology used, and their criticism has been confirmed by climate modellers, who have recently recognised that such proxy studies systematically underestimate past variability. As one Met Office scientist put it: "We cannot make claims as to the 1990s being the warmest decade."

Scientists at the UK Met Office and other IPCC stalwarts were among those who reported late last year in Science that the hockey stick analysis "contains assumptions that are not permissible".

It seems to me that this is a pretty important admission. The "warmest decade" cut-phrase from MBH was how Kyoto was sold in Canada. The UK Met Office doesn’t seem to have disseminated this information with as much fanfare as the prior claim that it was the warmest decade.

Update: the article from last year mentioned above would be von Storch et al. in Science. Roger Bell suggested that the Met Office scientist in question was probably a co-author of von Storch et al. [2004]. Simon Tett of the Hadley Center was a co-author .

42 Comments

The author of the first article misses out the fact that the climate models which are meant to demonstrate present climatic warming as "man-made" are calibrated using data derived from reconstructions of the past that may be very wrong. Also the publication of climate modelling runs is subject to a publication bias on the part of the modeller – the ones reported are what the modeller expects.

Is this what climate science has come to: "How lucky do you feel?" Whatever happened to empirical evidence and theoretic coherence?

Now all we need is a VERY PUBLIC WITHDRAWAL of the hockey stick. “So sorry. After properly scientific attempts to verify the “hockey stick” we have determined that it is not an accurate representation. Please delete it from all literature and considerations. It turns out there is nothing unusual about the present climate.”

One would think that even the BBC, referred to as a British Institution on 4/20/05, would want to contradict the UK Meteorological Office on meteorological matters. However, we’ll see if they mention the recent Met Office views.

It seems quite reasonable not to publish the results of modelling which are clearly well outside likely outcomes. Look what happened with the recent publication of the possible 11 degree C temp increase. The press jumped on it, despite the fact that those doing the work said it was not a likely scenario.

Climateprediction.net
Natural Environment Research Council
Oxford University
Embargoed until 1800 hrs (GMT) 26 January, 2005Bleak first results from the world s largest climate change experiment

Greenhouse gases could cause global temperatures to rise by more than double the maximum warming so far considered likely by the Inter-Governmental Panel on Climate Change (IPCC), according to results from the world s largest climate prediction experiment, published in the journal Nature this week.

The first results from climateprediction.net, a global experiment using computing time donated by the general public, show that average temperatures could eventually rise by up to 11°C – even if carbon dioxide levels in the atmosphere are limited to twice those found before the industrial revolution. Such levels are expected to be reached around the middle of this century unless deep cuts are made in greenhouse gas emissions.

Chief Scientist for climateprediction.net, David Stainforth, from Oxford University said: Our experiment shows that increased levels of greenhouse gases could have a much greater impact on climate than previously thought.

Climateprediction.net project coordinator, Dr. David Frame, said: the possibility of such high responses has profound implications. If the real world response were anywhere near the upper end of our range, even today s levels of greenhouse gases could already be dangerously high.

I’m sorry, Paul, but your thesis does not hold water. The people at climateprediction.net clearly pushed the button marked “Maximum scary headlines”. They did not emphasize how unlikely the upper bound was – they instead emphasized the reverse that the current expectations for future temperature were too low. The press in his case did not exaggerate what these people had said.

It would not be fair to say that they wrote to Nature saying, hey look our modelling shows a possible temperature rise of 11 degrees. Though the figure does appear in the abstract. My point was that you cannot critisise people for not releasing data which shows extream (if unlikely) scenarios but alo critisise them for exagerating risks, or scaremongering when they do.

Sorry, people, in response no 5 above, “would want” should be replaced by “would not want”.
In order to find out names of the Met Office sceptics, couldn’t someone just look at Science of last year and find the paper to see who has a Met Office affiliation? And who is an IPCC stalwart – Cubasch, von Storch,… I’d do it myself but the nearest Science is some way away.

Steve, From his comments, I’m not sure that Simon Tett is your mole.
To change the subject, we’ve had a very good high resolution solar atlas available for a number of years – it was observed at Kitt Peak. Now of course we astronomers have used it as a basis for comparisons with solar spectra computed from solar models, chemical abundances, oscillator strengths and what have you. However, we can also see terrestrial (aka telluric)lines in the solar spectra, particularly water vapour lines. Does anyone reading this know if the climate modellers have made any comparisons of their results with these spectra? Furthermore, do the climate modellers use the detailed solar spectrum, including all the absorption lines, as input to their models terrestrial atmospheric models?

This is a little outside my area. My understanding is that climate modelers use broadband infrared models, which parameterize narrow band and line models, and do not themselves independently calibrate infrared. Thus if there are errors in the water vapor NIR in HITRAN, as Belmiloud and others have argued, there will be a knock-on effect. What intrigues me is that the underestimate of NIR water vapor absorption seems to me to be exactly consistent with the problem. I’ve got a comment from Alan Arking on this that I meant to post up a while ago, but I’ll do so. steve

Steve,
I think that the complaints about errors in water vapour oscillator atrengths refer to Hitran96. I’ve got a copy of the latest version but don’t know if I’ll get around to using it – I’ve been retired for seven years now. Look forward to Arking’s comment.

OT – Roger, I was in a undergraduate astronomy class taught by David Lambert at UT when Hans Bethe walked in and gave us a lecture on the CNO cycle. Hope you have time to drop in on undergraduates. I had him sign a HR diagram before he left. He did so with a laugh as you might expect. It was fun watching him wonder about it. Hoped to leave him puzzled as it was obvious he enjoyed them. It might make a better story if he signed it Hertzsprung but he played it straight.

This from AP. It was in today’s Wall Street Journal. It is short enough to quote in full.

“Study of Ocean Data Backs Global Warming

NEW YORK-Climate scientists armed with new data from deep in
the ocean and far into space have found that Earth is absorbing much
more heat than it is giving off, a conclusion they say validates projec-
tions of global warming.
Lead scientist James Hansen, a climatologist for the National Aeronau-
tics and Space Administration, described the findings on the planet’s
out-of-balance energy exchange as a “smoking gun” that should dispel
doubts about forcasts of climate change. His team, reporting yester-
day in the Journal Science, said it also determined that global temperatures
will rise 1 degree Fahrenheit this century even if greenhouse gases are
capped tomorrow.
The NASA-led scientists calculated oceans’ heat content and the
global energy imbalance. They found that for every square meter of surface
area, the planet is absorbing almost one watt more of the sun’s energy than
it is radiating back into space as heat. Such absorbed energy will steadily
warm the atmosphere.”

So of the 235 watts per square meter that hit the surface, 234 return to space
right now says Mr. Hansen. .0043 from even. If Hansen thinks our past climate
history the result of extra-terestrial causes almost exclusively, but not now so
afflicted :), I can understand +.0043 alarming him. Otherwise I can’t see why
he is getting so excited. My assumption is that Hansen acknowledges significant
climate change in the last 2500 years even before the industrial revolution.

Otherwise, shouldn’t he have been surprised to see it zero. I’d think it would only average zero over a very long period of time and might be chaotically above or below for centuries.

OK. Maybe I’m dense today but how did “The NASA-led scientists calculated oceans’ heat content’ with enough precision to give a 1W heat imbalance? We lowly humans have only explored a small part of the oceans, let alone establish a comprehensive temperater gathering system. In the top 2 or 3 meters I suspect the temperature gradient is variable enough to require an accurate temperature for every liter of near surface water in all the oceans on a daily basis for several years. Anyone have a source for this? How about accurate temperatures for the rest of the ocean water? Maybe one data point per cubic meter down to 100m depth then for every 100 cubic meters for the rest. The water deeper than 1km is probably stable enough (unverified assumption) that we only need one set of data for the period in question.
A rough order calculation requires that the temperatures be accurate to better than 0.01C to get the estimation error down into the 1W per meter range. I could easily be off by an order of magnitude so I am not claiming anything other than curiosity.
And for a final bit of complication, what about the underwater sources of heat such as volcanic vents?

John, that story is covered by the BBC as well here, and I think has been mentioned elsewhere on this site.

The “usual suspects” are involved, Gavin Schmidt, James Hansen, who seem to have a remarkable ability to run a few computer models, claim it undeniably proves the world will end, and attract the attention of half the worlds press.

I’m just amazed that they can make the claim that this somehow validates the use of models to make future predictions. “We subtracted two sets of big numbers from our gigantic congruential multiplier*, came out with a positive number, therefore we can claim it is unprecedented and predict the behaviour of a coupled non-linear system a hundred years from now (in spite of having no actual hard data)”. I can’t help there is the teeniest leap of faith buried somewhere in that sentence.

* Side note: It has just dawned on me what GCM stands for! It’s gigantic congruential multiplier. Why hadn’t I thought of that before 🙂 Makes a good in-joke for computer nerds!

Spence, Thanks for the BBC link. It has a Gavin Schmidt quote that has me confused.

“What we are doing now is we are changing that imbalance at a rate which appears to be unprecedented over at least a thousand years”

He does say that the rate of change, and not the magnitude, are unprecedented? So no claim that a 0.85 W/sq m excess is the largest in the past 1000 years? Just that it got to 0.85 W/sq m faster? Was it 1.5 W/sq m a couple of years ago?

I know what he tried to say :). I think. The reporter didn’t get it right.

“The important point is that the planetary radiation imbalance is measurable, via the ocean temperature, because the only place this excess energy can go is into the ocean and, probably to a less extent, into the melting of ice.”

I would think the continents would suck up a lot of heat. Perhaps the last Ice age left some land cold to this day. They still find mammoth remains melting out of the ice.

If true Hansen should measure this and add it in. It would bolster his argument.

Re #22 this from http://abcnews.go.com/Technology/wireStory?id=713349 “The NASA-led researchers were able to measure Earth’s energy imbalance because of more precise ocean readings collected by 1,800 technology-packed floats deployed in seas worldwide beginning in 2000, in an international monitoring effort called Argo. The robots regularly dive as much as a mile undersea to take temperature and other readings.” Re volcanos, oh dear I’m surprised at you Michael suggesting that nonsense… just do the maths. There is NO WAY AT ALL, NONE, ZIPPO that volcanos can be the source of the heating up the worlds oceans (I’ve seen the calculation done – and if you insist I’ll try to find them).

Re #27. C’mon, John. Continental climates? Continents warm up AND cool down hugely on a annual basis. That’s nothing to do with cold left over from the ice ages.

The paper that led to the WSJ article in #12 can be found here http://pubs.giss.nasa.gov/docs/2005/2005_HansenNazarenkoR.pdf
and it concludes:
“A caveat accompanying our analysis concerns the uncertainty in climate forcings. Good fit of observed and modeled temperatures (Fig. 1) also could be attained with smaller forcing and larger climate sensitivity, or with the converse. If climate sensitivity were higher (and forcings
smaller), the rate of ocean heat storage and warming “in the pipeline” or “committed” would be greater, e.g., models with sensitivity 4.2-4.5°C for doubled CO2 yield ~1°C “committed” global warming (3, 4). Conversely, smaller sensitivity and larger forcing yields lesser committed
warming and ocean heat storage. The agreement between modeled and observed heat storage (Fig. 2) favors an intermediate climate sensitivity, as in our model. This test provided by ocean heat storage will become more useful as the period with large energy imbalance continues.
Even if the net forcing is confirmed by continued measurement of ocean heat storage, there will remain much room for trade-offs among different forcings. Aerosol direct and indirect forcings are the most uncertain. The net aerosol forcing that we estimate, -1.39 W/m2, includes a large
positive forcing by black carbon and a negative aerosol indirect forcing. Both of these aerosol forcings reduce sunlight reaching the surface, and may be the prime cause of observed “global dimming” (32) and reduced pan evaporation (33).
Given the unusual magnitude of the current planetary energy imbalance and uncertainty about its implications, careful monitoring of key metrics is needed. Continuation of the ocean temperature and altimetry measurements is needed to confirm that the energy imbalance is not a fluctuation and determine the net climate forcing acting on the planet. The latter is a measure of the changes that will be needed to stabilize climate. Understanding of the forcings that give rise
to the imbalance requires more precise information on aerosols (34). The high rate of recent eustatic sea level rise that we infer suggests positive contributions from Greenland, alpine glaciers, and West Antarctica. Quantification of these sources is possible using precise satellite altimetry and gravity measurements as initiated by the IceSat (35) and GRACE satellites (36), which warrant follow-on missions.”

Hardly a clear-cut conclusion or a “smoking gun” as Hansen is quoted as claiming.

Peter,
I did not imply that underwater sources of heat such as volcanic vents are responsible for heating up the oceans. I implied that their non-zero contribution may be a significant source of error in the calculations. Does it change their value by 0.1%, 1% or maybe even 10%?
As for the 1800 data gathering modules. Having a lot more data than before is great but it does not neccessarily mean there is enough accurate data to make the claims they are making. At best it is a much better guestimate of the heat content of the oceans. Not the same thing at all. Just to put on sample point per square kilometer you need 201000 times that number of sensors and it will still be a rough estimate. A lot better but still only an estimate. Think of it as measuring the body temperature of 10 people in europe to the nearest 2 degrees and then stating that the average temperature for all Europeans is 36.800013C which is 0.000005C cooler then 3 years ago.
I also noted in the article that the 0.85W number “agreed” with their model so it must be right in their opinion.

In fairness to Hansen, the caveat concerns the analysis of how the ‘imbalance’ affects ongoing predictions of temperature rise, not the measurement of the inbalance itself. But I have tons of questions about the measurements themselves which will have to await getting access to the actual article itself. But I think we can guess how difficult it’s going to be to do a real audit of this data.

This is a topic I know less about, but I would agree with you that the surface of the earth varies up and down considerably, but as soon as you go a few metres down that doesn’t apply. I say this primarily from experience of going into mines – temperatures in mines are rock (sic) solid steady, on the hottest day of the year and the coldest day of the year.

Here is an example discussion I looked up on the web. Sounds to me like there is a massive potential well of energy under the continents, although the inertia (time taken to put the energy down there) will be massive compared to the seas, which have the advantage of convection as well as conduction.

Spence, exactly so. #27 was a bit of a troll. Having read “Earth’s Energy Imbalance” the bit on sea level change was well done. I think, and have thought before, it good evidence of warming. I also think the seas do act much like he says as the major source of thermal inertia in multi decade even century time frames. What I don’t get is an anthropogenic “smoking gun”. Perhaps we live in a strangely volcanically uneruptive times. Perhaps the sun’s irradiance has gone up by .44 W/m2 since 1880 but had gone up 2 W/m2 or more in the 1700s and the oceans’ thermal inertia is large enough for our global temperature to be going up only now.

if they say “The net change of effective forcing between 1880
and 2003 is +1.8 W/m2, with formal uncertainty ±0.85 W/m2…”, surely that means they think it’s somewhere between +.95W/m2 and + 2.65W/m2 (95% confidence I guess)? You can call it NO SCIENTIFIC etc etc if you like but that’s just your, somewhat shouted, OPINION 🙂 Why? Because I’m sure the authors wouldn’t agree with you.

Peter, you really should read the referenced paper before commenting. You took a comment on something completely out of context, turned it into something completely different from what is in the paper and then ranted about it. The claimed change of 1.8 is from about -.85 to +.85, not .85 to 2.65.
Here is a more complete quote of a relevant section complete with a caveate that the long term average must be very close to 0.0.
“Earth’s energy imbalance. We infer from the consistency of observed and modeled planetary energy gains that the forcing still driving climate change, i.e., the forcing not yet responded to, averaged ~ 0.75 W/m 2 in the past decade and was ~ 0.85 ± 0.15 W/m 2 in 2003 (Fig. 1C). This imbalance is consistent with the total forcing ~1.8 W/m 2 relative to 1880 and climate sensitivity ~2/3°C per W/m 2. The observed 1880-2003 global warming is 0.6-0.7°C (10, 21), which is the full response to nearly 1 W/m 2 of forcing. 0.85 W/m 2 of the 1.8 W/m2 forcing remains, i.e., additional global warming of 0.85 x 2/3 ~ 0.6°C is “in the pipeline” and will occur in the future even if atmospheric composition and other climate forcings remain fixed at today’s values (3, 4, 22).
The present planetary energy imbalance is large by standards of Earth’s history. For example, an imbalance of 1 W/m 2 maintained for the last 10,000 years of the Holocene is sufficient to melt ice equivalent to 1 km of sea level (if there were that much ice), or raise the temperature of the ocean above the thermocline by more than 100°C (table S1). Clearly on long time scales the planet has been in energy balance to within a small fraction of 1 W/m 2.”

Firstly, look up ‘rant’…Secondly I accept you corrections to uncertainties 🙂

The last sentence you quote means what it says. If the planet wasn’t, over the long (geological) term, in energy balance, temperatures would show a long term rising trend – they do not (but, of course they do show warming atm).

1w/m2 is clearly a lot of imbalance – we’re headed that why. It might not concern you, but it sure as heck concern me.

Peter, what concerns me is that the human race is forgetting how to adapt to a changing climate and is actively taking steps to make it harder to adapt. The climate has a long history of change, sometimes quite dramatically. This occurs whether man is here or not. The only reason we are here today is because we were pretty good at adapting to the last big cycle. Heading south to outrun another ice age would be difficult, if not impossible, for most of the population of the northern hemisphere. I read arguments about doing something to try and control the global temperature for the next hundred years. I see nothing about investing in improving our ability to adapt to changes over the next 1,000 or 10,000 years.
All this focus on a minor GHGs without looking at the whole picture is too much like walking out onto the sand to stare at the interesting sea creatures who have been left high and dry by the rapidly receding waters of a mega-tsunami. I think you know what happened to those short sited people.
Unless we are prepared to think and act long term and switch over to an energy process, such as nuclear or space solar, that does not generate any GHGs then the discussion of whether anthropic CO2 is warming the atmosphere significantly is pointless. If, despite all our advancements, we have become that short sited then we are just another failed experiment waiting to be overcome by the next great attempt at truly intelligent life on this planet.

Chaps.
Driving to work this morning, i heard a report on the BBC that stated, coastal salt marshes are under thresat from rising sea levels. As a complete layman in this field, i wonder if some of you could clarify if sea levels are indeed rising.